The invention relates to a tape viewer for use with a cassette tape recorder, and more particularly to a tape viewer which enables the winding or running condition of a magnetic tape contained in a tape cassette which is loaded into a cassette tape recorder to be monitored by visual inspection through a viewing window formed in the cassette.
A conventional tape cassette is formed with a monitoring window formed by a transparent material which is located intermediate a pair of winding and take-up reels contained in the cassette in order to permit a determination to be made as to how much of the tape is disposed on either one of these reels. However, the small size of the viewing window makes the visual inspection difficult to achieve. On the other hand, a tape cassette which is loaded into a cassette receiving chamber formed in a tape recorder is covered with a dust-proof lid, so that the tape contained within the cassette must be viewed through a pair of windows, namely, the viewing window formed in the cassette and a sight window formed in the lid, thus degrading the amount of available light. Additionally, the sight window is surrounded by a dark panel of a reduced transmittance which is employed for purpose of providing a sightly design, thus further degrading the available light. In order to overcome such difficulty, it has been proposed to provide an illumination lamp within the cassette receiving chamber at a location which corresponds to the viewing window, or to apply a reflector of a high optical reflectivity to a portion of the bottom wall of the cassette receiving chamber which is opposite to the viewing window.
However, with a miniaturization of the cassette as may be exemplified by a micro-cassette developed by the present applicant and which has a size comparable to a packet of matches, the possible size reduction of the viewing window is limited, and the use of the illumination lamp or the reflector is prohibitive. A tape recorder of a miniature size which is used to operate on a micro-cassette is operated by a battery of a reduced capacity, so that the power dissipation involved with the use of the lamp is undesirable. Because the viewing window has a reduced size to result in a reduced amount of light which is admitted, the provision of the reflector is ineffective to provide satisfactory illumination.